Refrigeration Purger Monitor

Abstract

An industrial refrigeration system has a purger for removing non-condensable content extracted from a volume of refrigerant. The purger separates a quantity of refrigerant from a mixture of refrigerant and air and purges the air and a portion of the refrigerant. The purger includes a control unit and an algorithm that estimates the purged quantity of refrigerant from measured and stored refrigeration and purger operating parameters.

What is claimed is: 
     
         1 . A refrigeration purger system comprising:
 a purger unit having an upper chamber and a lower chamber in fluid communication with the upper chamber, and a head connected to the upper chamber;   at least one of a pressure sensor and a temperature sensor mounted on the head and configured to measure an associated state within the upper chamber; and   a control unit connected to the at least one pressure and temperature sensor, the control unit having an algorithm configured to control a purging cycle that purges air collected in the purger unit and determining an estimate of refrigerant loss during the purging cycle.   
     
     
         2 . The refrigeration purger system of  claim 1  wherein a float having a fluid level sensor is disposed within the upper chamber, the fluid level sensor measuring a refrigerant level and sending a fluid level measurement value to the control unit, the algorithm determining a volume of air in the purger and initiating the purging cycle based on the fluid level measurement and the measured state within the upper chamber. 
     
     
         3 . The refrigeration purger system of  claim 2  wherein the pressure and temperature sensors and the fluid level sensor are mounted to the upper chamber head, the algorithm estimating the volume of refrigerant using the temperature, pressure, and fluid level measurements within the purger and determining a volume of mixed air and refrigerant vented during the purging cycle. 
     
     
         4 . The refrigeration purger system of  claim 3  wherein the algorithm uses a purge length of time measurement to estimate the refrigerant loss during purging. 
     
     
         5 . The refrigeration purger system of  claim 1  wherein the algorithm includes at least one refrigerant lookup table having data associated with a refrigerant property as a function of temperature. 
     
     
         6 . The refrigeration purger system of  claim 5  wherein the lookup table includes data associated with at least one of a system operating pressure, a refrigerant density as a function of temperature, an air density as a function of temperature, a volumetric ratio of refrigerant to air as a function of temperature, and a weight ratio of refrigerant to air as a function of temperature. 
     
     
         7 . The refrigeration purger system of  claim 5  wherein the control unit transfers the refrigeration loss estimate to a computer. 
     
     
         8 . The refrigeration purger system of  claim 1  wherein a condensing channel fluidly connects the upper chamber to the lower chamber. 
     
     
         9 . The refrigeration purger system of  claim 8  wherein the lower chamber is configured as one of an inverted bucket trap and a ball float trap. 
     
     
         10 . The refrigeration purger system of  claim 1  wherein a coil is disposed within the upper chamber, the coil being in fluid communication with a refrigerant source such that the control unit maintains a condensing temperature within the upper chamber. 
     
     
         11 . The refrigeration purger system of  claim 10  wherein the control unit operates at least one purger operational valve to control the condensing temperature in response to the temperature within the purger. 
     
     
         12 . The refrigeration purger system of  claim 11  wherein the control unit operates at least one purge point valve to direct a flow of mixed refrigerant and air to the purger. 
     
     
         13 . The refrigeration purger system of  claim 12  wherein the algorithm includes at least one refrigerant lookup table having data associated with a refrigerant property as a function of temperature and pressure, the algorithm including data related to refrigeration system operating parameters. 
     
     
         14 . The refrigeration purger system of  claim 13  wherein the purger includes a fluid level sensor configured to send a signal to the control unit that is proportional to the refrigerant level in the purger, the algorithm determining a purge time based on one of a refrigeration level, the condensing temperature, and the pressure within the purger. 
     
     
         15 . The refrigeration purger system of  claim 14  wherein the refrigerant level sensor is a float level sensor. 
     
     
         16 . A control unit for a refrigeration purger system, the control unit having an algorithm configured to control a purging cycle that purges air collected in the purger unit and determining an estimate of refrigerant loss during the purging cycle, the algorithm having a refrigerant lookup table that includes data associated with at least one of a refrigeration system operating pressure, a refrigerant density as a function of temperature, an air density as a function of temperature, a volumetric ratio of refrigerant to air as a function of temperature, and a weight ratio of refrigerant to air as a function of temperature, the algorithm further using a purge duration parameter, a purger temperature parameter, and a purger refrigerant fluid level to estimate refrigerant loss. 
     
     
         17 . The control unit of  claim 16  wherein the control unit is operative connected to at least one purger operational valve to control the temperature within the purger and operatively connected to at least one purge point valve to control a flow of a mixture of refrigerant and air to the purger in response to the purger refrigerant fluid level. 
     
     
         18 . A refrigeration system comprising:
 a compressor;   a condenser in fluid communication with the compressor;   an evaporator in fluid communication with the compressor; and   a refrigeration purger system comprising:
 a purger unit having an upper chamber and a lower chamber in fluid communication with the upper chamber, a head connects to the upper chamber; 
 at least one of a pressure sensor and a temperature sensor mounted on the head and configured to measure an associated state within the upper chamber; and 
 a control unit connected to the at least one pressure and temperature sensor, the control unit having an algorithm configured to control a purging cycle that purges air collected in the purger unit and determining an estimate of refrigerant loss during the purging cycle. 
   
     
     
         19 . The refrigeration system of  claim 18  wherein the algorithm includes at least one refrigerant lookup table having data associated with a refrigerant property as a function of temperature and pressure, the algorithm including data related to refrigeration system operating parameters. 
     
     
         20 . The refrigeration system of  claim 19  wherein a coil is disposed within the upper chamber, the coil being in fluid communication with the compressor such that the control unit maintains a condensing temperature within the upper chamber, the upper chamber further including a fluid level sensor configured to send a signal to the control unit that is proportional to a refrigerant level in the purger, the algorithm determining a purge time based on one of a refrigeration level, the condensing temperature, and the pressure within the purger.